1. Mar 9, 2012

### albarnett17

A 1000-kg car moves at a maximum speed so that it does not skid off the 50-m radius level track. If the coefficient of static friction between the road and wheels is 0.80. What is the maximum speed? Assume that the gravitational constant is 10.0 N/kg =10.0 m/s. Use the simulations in 4.5 Car Circles a Track to check your answers.

Write an equation for the vertical y-component form of Newton's second law. Determine the magnitude of the normal force. Then use a force law equation to determine the magnitude of the static friction force.

Write an equation for the radial component form of Newton's second law. Use this to determine the maximum speed that the car can travel so that it does not skid (so that friction can provide the needed force to keep the car moving in a circle). Once you have calculated the maximum speed adjust the speed slider in the 4th simulation to this speed and see if the car stays on the track.

2. Mar 9, 2012

### tiny-tim

welcome to pf!

hi albarnett17! welcome to pf!

with these questions, do everything in the order the question tells you to

… what do you get?

3. Mar 9, 2012

### albarnett17

Idk any equations or where to put what in the equations i have no idea how to do this.

4. Mar 9, 2012

### tiny-tim

in other words:

draw a free body diagram

mark all the external forces on it

then do F = ma in the vertical direction​

what do you get?

5. Mar 9, 2012

### albarnett17

Ok i did i have a diagram but i still dont get sorry but i really do not kno like almost anything in physics

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6. Mar 9, 2012

### tiny-tim

ok, now we have to do F = ma vertically (in the y direction), from your diagram

a (acceleration) vertically is obvously zero, and your only vertical forces are the normal force N, and the weight (which you're calling V, but we usually call it W) …

ok so what is the equation (with the numbers in)?

7. Mar 10, 2012

### albarnett17

F=10000*0
f=0

8. Mar 10, 2012

### tiny-tim

what's F?

9. Mar 11, 2012

### albarnett17

f= 0

10. Mar 11, 2012

### tiny-tim

yes, but what is F made of?

11. Mar 11, 2012

### albarnett17

Force idk m*g

12. Mar 11, 2012

### tiny-tim

m*g = 0 ?

13. Mar 11, 2012

### albarnett17

im so confused man heres what i got for
question 1.F(n) = mg
F(n) =(1000)(9.81)
F(n) =9810 N
SF=UF
SF=(0.80)(9810)
Sf=7848

14. Mar 11, 2012

### tiny-tim

hi albarnett17!
ok so far

(except thequestion says g=10 N/kg, so the friction force is 8000 N)

now use that in F = ma for the x direction